Furnace-twyer.



No. 706,332. Patented Aug. 5, |902.

E. H. MESSITER.

FURNACE TWYER.

(Application tiled Nov. 26, 1901.)

(No Model.)

TTn STATES PATENT OFFICE.

EDWIN Il. MESSITER, OF SAN LUIS POTOSI, MEXICO.

FuRNACE-TWYER.

SPECIFICATION forming part of Letters Patent N o. 70 6,332, dated August5, 1902.

Applica/tin led November 26, 1901. Serial No. 83,773. (No model.)

To all whom t may concern.-

Beit known that I, EDWIN H. MESSITER, a citizen of the United States,residing at San Luis Potosi, in the State of San Luis Potosi, Mexico,have invented certain new and useful Improvements in Furnace-Twyers, ofwhich the following is a specification, reference being had therein tothe accompanying drawings.

This invention relates to improvements in twyers and twyer-boxes forconducting air to furnaces of any of the several sorts which in smeltingand kindred arts require that air be supplied thereto under more or lesspressure.

The object is to permit the free and prac- I tically unobstructedintroduction of the air to the furnace and at the same time prevent abackward flow of gases or air at any time through the blast-pipe andaiford an instantaneous relief for such back pressure when there is atendency toward reversal of current. There is great danger of explosionin the blast-pipe resulting from such backward iiow or reversal of thecurrent. Such backflow frequently occurs, as when the pressure issuddenly cut olf either intentionally or in case of accident to thecompressing or blowing mechanism or to the ducts through which the airis carried to the twyer. At the same time it is not only desirable, butunder many circumstances absolutely necessary, to not only thus checkthe backiow of gases and air through theair-ducts,butalsorelievethetwyerpart and the furnace entirely therefrom, this being demanded forseveralreasons,including the possibility of leakage past the valve or deviceused for normally checking the backflow, even though closed.

My invention can be embodied in either of several forms of device. Ihave selected for illustration one which presents the essential featuresof structure and the mode of operation, but wish it to be understoodthat I do not limit myself thereto, as there can be modification withoutdeparting from the invention.

Figure l is a vertical sectional View of a portion of a furnacesul'licient to illustrate the manner of applying my inventionthereto.Fig. 2 is a top view of the twyer and the end of the blast-pipe. Fig. 3is a plan view with the top casing-plate removed. Fig. 4 is a sectionalview on line IV, Fig 1.

In the drawings, A represents the blast pipe or duet through which theair is brought to the twyer, the latter being indicated by B. Betweenthese there is placed the check-valve C, which may be of the ordinary orof any preferred construction, it being hingedat c and having a seat c',against which it normally tends to press when relieved of pressure inthe pipe A.

D is the chamber wherein the valve C swings when movingffrom and towardits seat, the dotted lines at d indicating the position occupied by itwhen air (under ordinary conditions as to pressure) is passing from thepipe A to the twyer B.

ItY has been customary heretofore to provide a device for checking thebaekliow of the gases which is normally held open by the static pressureof the air flowing through the twyer and which is closed when the staticpressure is reduced below a certain amount, at the same time opening arelief-port to the atmosphere. When the blowing apparatus is graduallyslowed down in the usual way, the static pressure in the twyers isreduced to a small amount by the gradual escape of the gases through thefurnace before the iiow of air through them toward the furnace ispermitted to cease by the stopping of the blowing apparatus, and thedevices heretoforeused will act before the forward motion oftheblast'stops. It is in cases of sudden stoppage or disconnection of thesource of pressure through accident or otherwise that the backiow ofgases from the furnace occurs with the most serious results. In thesecases the conditions are very different. The backow is theninstantaneous and precedes any material reduction in the static pressurein the twyers, and consequently precedes the action of the devicesheretofore used.` It is the object of my invention, therefore, tocombine a device for preventing backliow of the gases which is closedwhen the dynamic pressure due to theimpact of the blast against it isreduced, regardless of the static pressure, with a relief-port normallyclosed by a device which will open said ,port when the first-mentioneddevice is lclosed and an eX- eess of pressure on the furnace side of itexists. In other words, the object is to provide a mechanism which willprevent backtlow of gases under any and all conditions and which willafford relief for any back` pressure which may exist.

I provide a separate outlet for the reacting IOO gases-that `is to say,an outlet cut olf from the blast-pipe A and through which thebacktlowing gases can escape to a region of low pressure, either aninclosed compartment or to the open atmosphere, preferably the latter`and with suc-h outlet combine means which' hold it closed under normalWorking conditions, but which instantly open it when from any cause thepressure on the twyer side of the check-valve becomes greater than it ison the inlet side. The device which I have illustrated for attainingthis part of the invention consists of the'outlet-passage e, adapted tocommunicate with the chamber D of the twyerand also with the ori ticeE,which in the construction shown leads to the open atmosphere. Thisoutlet-duct e is shown as being a groove or channel formed in the metalat the upper part of the valve-chamber D. F is a valve or closing devicefor this outletduct. It may be normally held to its seat and in itsclosed position by any suitable device orragency, so that it be capableof yielding if the pressure on the inner side of lthe check-valve shouldat any time become too great for safety in relation to the pressure inthe blast-pipe A. For holding this valve F to itsseat I prefer to followthe plan herein illustrated.. I provide a closed chamber G for thevalve, wherein it is permitted to have suiicient movement to accomplishits purposes. This chamber can be provided by forming a flange H ofring-like character above the valve-chamber D and closing the spaceencircled by it by means of a plate I and bolting it to the flange, asshown at i. 'lhe chamber G communicates with the blastpipe A by one ormore ports g, which are reduced in cross-areain such way that they willmaintain in the chamber G a pressure equal lo that in the blast-pipe A,but will not permit a backliow'of air from the chamher G except veryslowly. l The valve or plate F will be held downcon its seat by anexcess of pressure on its upper or outer side, such excess arising fromthe fact that part of the surface of its under or inner side is eX-posed to'a relatively low pressure-`-as, for instance, 'that of theatmosphere. Being tight on its seat atf, this Valve or`platewill permitno leakage from the twyer, and under normal conditions when the deviceis in operation it will act simply as acheck-valve.

, If now the liow of air from the inlet side to the outlet side of thevalve C ceases from any cause or if there should be a sufficient drop inthe pressure, this valve will close under the action of gravity, and ifthere should be any tendency to a backward flow of gases- .that is, aflow from the outlet side to the inlet side-the pressure on the inletside becomes less than that on the outlet side, and if this reversal ofthe pressure increases to an appreciable extent the supplemental valveor plate F will move from its seat and communication will be openedbetween the twyerl mouth or the chamber D and the duct E andescape-outlet c. The gases under pressure vin the furnace will then beallowed to escape to the openair or other region of relatively lowpressure, and the pressure in the twyerchamber-that is, the pressure onthe outlet side of the check-valve C-will be reduced practically to thatof the atmosphere. The orifice g being, as aforesaid, relatively smallin area in comparison withthe area of the duct E and the outlet e, thereacting gases from rthe furnace will escape through said at g. When thenormal working conditions are restored by forcing the air again throughthe inlet part of the twyer, the valves Cand region of pressure lowerthan that in either of theaforesaid ducts and a closing device for saidlow-pressure duct independent of the said gas-check means, substantiallyas set forth.

3. In a furnace blast mechanism an air-introducing mechanism having afurnace-d uct, a blastduct communicating therewith, a check-valvebetween the f u-rnace-duct and the blast-duct, an atmosphere-ductadapted to communicate with the furnace-duct, a valve for theatmosphere-duct movable independently of the first aforesaid valve andadapted to be closed when the first said valve is closed, substantiallyas set forth.

v4. The combination of the twyer duct or outlet B, the blast or inletduct A, the automatically-acting means for closing the duct Aagainstbackflow of gases, the escape-passage E adapted to communicate with thetwyer to connect the latter with an exterior the escape-passage, the twosaid closing devices being adapted to be closed simultaneonsly and to beopened independently of each other, substantially as set forth.

5. In a furnace blast mechanism an air-introducing device having a maincheck-valve, a duct on the outside of said valve, a furnaceduct on theinner side of said valve, a supplemental escape-duct relatively on theinner side of said valve adapted to connect the furnace-duct with aregion of relatively low presthe plate or valve F will resume theirposispace and a second closing device for closing duct andorice and notthrough the passage the inlet-duct, a duct communicating with a IOO IIO

sure and a supplemental valve movable independently of the maincheck-valve for closing the escape-duct, substantially as set forth.

6. In a furnace blast mechanism anair-introducing device having acheck-valve, an inlet-duct on the outer side of said valve, anoutlet-duct on the inner side of said valve, an escape-duct adapted toconnect said inletduct with a region of relatively low pressure, asupplemental valve held closed by the pressure in the inlet-duct andinterposed between the outlet-duct and the escape-duct, substantially asset forth.

7. In a furnace blast apparatus an air-introducing mechanism having afurnace outletduct, a blast inlet-duct, two passage-ways from theinlet-duct to the fu rnace outlet-duct, two closing devices, one foreach of said passage-ways, and a supplemental outlet-duct adapted tocommunicate with the furnace outlet-duct, said supplemental outlet beingclosed by one of said closing devices, substantially as set forth.

S. In a furnace blast apparatus an air-introducing mechanismhavingafurnace outletduct, a blast inlet-duct, two passage-ways from theinlet-duct to the furnace outlet-duct, two closing devices, one for eachof said passage-ways, and a supplemental outlet-duct adapted tocommunicate both with the aforesaid outlet-duct and with the inlet-duct,said supplemental outlet-duct being closed by one of the said closingdevices, substantially as set forth.

9. In a furnace blast apparatus the air-introducing mechanism having achamber D, three ducts adapted to communicate with said chamber, theiirst duct also communicating with an air-forcing mechanism, the secondduct communicating with the interior of a furnace, and the third ductcommunicating with the open atmosphere, and two independent valves, oneinterposed between said chamber and the open atmosphere-duct, and oneinterposed between the said chamber and the blast-duct, and one beingheld open and the other held closed independently of each other by theair-blast, substantially as set forth.

l0. In a furnace blast mechanism an airintroducing device having aninlet, a furnaceoutlet, a check-valve between the inlet and the outlet,a supplemental outlet connecting the furnace-outlet with a region ofpressure lower than that of the air-blast, a valve between said twooutlets and a duct supplemental to the check-valve passage to carry airfrom the inlet to the second valve to hold it closed.

ll. In a furnace blast mechanism an airintroducing device having acheck-valve, a duct on the outer side of the valve, a furnaceduct on theinner side of the valve, a duct adapted to connect the furnace-duct withthe open atmosphere, a valve for said duct supplemental to andindependent of the checkvalve, a pressure-chamber on the outer side ofthe supplemental valve and a duct adapted to connect saidpressure-chamber with a region of relatively high pressure,substantially as set forth.

l2. In a furnace blast mechanism an airintroducing device having acheck-valve, an inlet-duct on the outer side of said valve, afurnace-duct on the inner side of said valve, an escape-duct adapted toconnect the furnace-duct with the open atmosphere, a valve supplementalto the check-valve for closing said escape-duct, a pressure-chamber forthe supplemental valve and a reduced port connectin g saidpressure-chamber with the first aforesaid duct on the outer side of thecheckvalve, substantially as set forth.

I3. In a furnace blast apparatus the airintroducing mechanism having achamber as at D, three ducts7 the first adapted to communicate with saidchamber, the second being a furnace-duct permanently communieatingtherewith, and the third being an atmosphere-duct intermittentlycommunicating therewith, a gravityvalve introduced between the firstduct and said chamber D and adapted to be opened by the air-blast, agravity-valve interposed between the said chamber and theatmosphere-duct and normally held closed by the blast, substantially asset forth.

14. The combination of the twyer, the blastduct, anautomatically-operative check-valve between the same, a relief devicecommunicating with the twyer, and means whereby the operation of saidrelief device is determined by a difference of pressure in saidblast-duct and twyer when cut off from each other by said check-valve.

15. The combination ofthe twyer, the blastduct, an escape-duct from thetwyer, means whereby said escape-duct is closed by the pressure of theblast, and an automaticallyacting check-valve between the twyer andblast-duct.

1G. The combination of the twyer, the blastduct, an automatically-actingcheck-valve between the same, an escape-duct, passages from each side ofthe check-valve communieating with said escape-duct, and a supplementalvalve acting to close the passage from the twyer and from the blast-ductto the escape-duct.

17. The combination of t-hetwyer, the blastduct, an automaticallyactingcheck-valve between the same, an escape-passage from the twyer to anouter region of relatively low pressure, a supplemental valvecontrolling said escape-passage, and means whereby the pressure in theblast-duct acts on said supplemental valve in the direction in which thesame closes.

In testimony whereof I affix my signature in presence of two witnesses.

EDWIN H. MESSITER.

Witnesses:

RAMONA VELAZQUEZ, CHARLES AsHBY VAUGHAN.

ICO

